The patent application US 2006/0261226 A1 discloses a flat panel display wall mounting system that includes a plate assembly connected to a flat panel display mounting rack assembly. The wall plate assembly, which is separated from the rack assembly during mounting on a wall, is provided with a bar and two angled slots. The wall plate assembly is attached to the wall by anchoring elements disposed through these angled slots. The angled slots serve to level the wall plate assembly on the wall. Once the wall plate assembly is leveled, the wall plate assembly is further secured to the wall. The rack assembly, which is provided with a U-shaped channel, is mounted to the flat panel display. Once the rack assembly is connected to the flat panel display and the wall plate assembly is attached to the wall, the flat panel is lifted to a position in which the U-shaped channel of the rack assembly engages the bar of the wall plate assembly, whereafter the flat panel display hangs on the wall plate assembly and thus on the wall.
Although the wall plate assembly is provided with angled slots for leveling purposes, the known system has the disadvantage that a horizontal adjustment of the mounted flat panel display is not possible. It has proved that already a small deviation of the exact horizontal orientation of the mounted wall plate assembly or a small tolerance difference in a component of the mounting system often results in an unacceptable deviation of the horizontal orientation of the mounted flat panel display. Generally, it is very difficult for customers to horizontally mount a flat panel display on a wall. Even with the use of an appropriate tool, such as a level, tolerances in the applied mounting mechanism implicate that the mounted flat panel display is rarely completely horizontally aligned.